What are the characteristics of a lake?
Characteristics of a lake
Lake as a natural water body which contains water almost throughout the year. Lakes are much deeper compared to ponds. Light in aquatic medium cannot penetrate beyond a depth of 200 meters. Hence vegetation in an aquatic medium does not occur below 200 meters. Thermal stratifications occur in lakes of temperate regions. Oxygen is poor in the deeper waters. Three zones can be recognised in a lake. They are littoral zone, limbnetic zone and profundal zone. All Biology Doubts are explained by academic team of Physics Wallah.
1. Littoral zone
The region close to the shoreline of the lake constitutes the littoral zone. Light can penetrate upto the bottom because of the shallow waters. Vegetation is abundant and therefore the dissolved oxygen content in the water is high. Consumers also are abundant in this zone. Water is relatively warmer as it is heated by the sun’s radiation.
B) Biotic communities :
The biotic communities in this zone are the producers and the consumers.
These are the rooted plants and the phytoplankton.
1. Rooted plants
The rooted plants are of three types: emergent vegetation, floating vegetation and submerged vegetation.
a) Emergent vegetation: Plants which are partly submerged and partly exposed are described as emergent plants or amphibious plants. These are fixed to the soil and obtain their nutrients from the soil.
e.g. Limnophila, Typha, Sagittaria etc.
b) Floating vegetation: The floating vegetation includes the five floating and rooted and floating plants. The broadleaves provide space for aquatic animals to rest and also for egg laying.
e.g. Pistia (free floating), Nymphaea (rooted and floating) etc
c) Submerged vegetation: Away from the bank is the rooted submerged vegetation. e.g. Vallisneria, Chara, Potamogeton.